New research is backing up the age-old advice of “Eat your vegetables.” This study, however, isn’t focused on how to prevent chronic and life-threatening disease. Rather, these scientists looked at the connection between healthy foods and happy moods.

How Scientists Tell Which Foods Make You Happy

At the University of Otago in New Zealand, Dr. Tamlin Conner (Department of Psychology) and Dr. Caroline Horwath and Bonnie White (Department of Human Nutrition) teamed up to see whether our day-to-day feelings are linked to what we eat.

To find out, they had 281 young adults keep an internet-based daily food diary for 21 consecutive days. The participants also answered questions about their age, ethnicity, gender, height and weight.

Each evening, they all rated how they felt in their diary using the same nine positive and nine negative adjectives for consistency. Plus, they answered questions about what foods they had eaten that day.

For example, they traced how much fruit (but not juice or dried fruit), and how many servings of vegetables they had that day. Plus, they reported several categories of unhealthy foods from which they had eaten. Examples of the unhealthy foods included biscuits, cakes, cookies, muffins and potato crisps.

What Can You Eat to Feel Happier?

The results showed a consistent and strong correlation only between better moods and higher fruit and vegetable consumption. When people ate larger portions of fruit and vegetables, they not only reported having more energy, but they also said they felt calmer and happier than usual.

Do We Eat Better when We Feel Good?

The researchers also considered the possibility that we take better care of ourselves with healthy food when we’re happy. With additional analyses, they realized that how much fruit and vegetables people ate could actually predict when they would be in a good mood the following day. That suggests that healthy foods actually cause happy moods. And, the results were true regardless of Body Mass Index. That’s how your height and weight are used to calculate your body fat.

How Much Good Food Does It Take to Make You Happy?

The research indicated people needed about seven to eight servings of fruits and vegetables per day to get a meaningful positive change in mood. A serving is about what could fit in the palm of your hand, or half a cup. Study co-author Bonnie White says the easy way to get that is by filling half your plate at each meal with vegetables and then snack on some whole fruit like organic apples.

Jim McFadden has over 11 years of executive-level experience in the health insurance industry, is a youth baseball, softball and football coach, and has one of the worst fantasy football records in the world.